Category: Military

This document was released to the general public by the United States War Department on August 12th, 1945, just days after nuclear weapons had been dropped on Japan (Hiroshima on August 6th and Nagasaki on August 9th). The author, Prof. Henry D. Smyth of Princeton University, had worked on the Manhattan Project since early 1941, was involved in a variety of theoretical and practical aspects of the effort, and possessed security clearances which gave him access to all of the laboratories and production facilities involved in the project. In May, 1944, Smyth, who had suggested such a publication, was given the go ahead by the Manhattan Project’s Military Policy Committee to prepare an unclassified summary of the bomb project. This would have a dual purpose: to disclose to citizens and taxpayers what had been done on their behalf, and to provide scientists and engineers involved in the project a guide to what they could discuss openly in the postwar period: if it was in the “Smyth Report” (as it came to be called), it was public information, otherwise mum’s the word.

The report is a both an introduction to the physics underlying nuclear fission and its use in both steady-state reactors and explosives, production of fissile material (both separation of reactive Uranium-235 from the much more abundant Uranium-238 and production of Plutonium-239 in nuclear reactors), and the administrative history and structure of the project. Viewed as a historical document, the report is as interesting in what it left out as what was disclosed. Essentially none of the key details discovered and developed by the Manhattan Project which might be of use to aspiring bomb makers appear here. The key pieces of information which were not known to interested physicists in 1940 before the curtain of secrecy descended upon anything related to nuclear fission were inherently disclosed by the very fact that a fission bomb had been built, detonated, and produced a very large explosive yield.... [Read More]